package com.etu.jsonservices.model;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.stereotype.Repository;

/**
 * This class serves as the Base class for all other DAOs - namely to hold
 * common CRUD methods that they might all use. You should only need to extend
 * this class when your require custom CRUD logic.
 *
 * Based on Bryan Noll's original GenericDAOHibernate.
 * <p/>
 * <p>
 * To register this class in your Spring context file, use the following XML.
 *
 * <pre>
 *      &lt;bean id="fooDao" class="org.appfuse.dao.hibernate.GenericDaoHibernate"&gt;
 *          &lt;constructor-arg value="org.appfuse.model.Foo"/&gt;
 *      &lt;/bean&gt;
 * </pre>
 *
 * @param <T>
 *            a type variable
 * @param <PK>
 *            the primary key for that type
 */
@Repository
public class GenericHibernateDAO<T, PK extends Serializable> implements
	IGenericDAO<T, PK> {
    /**
     * Log variable for all child classes. Uses LogFactory.getLog(getClass())
     * from Commons Logging
     */
    protected final Log log = LogFactory.getLog(getClass());
    private Class<T> persistentClass;

    @Autowired
    private HibernateTemplate hibernateTemplate;

    /**
     * Constructor that takes in a class to see which type of entity to persist.
     * Use this constructor when subclassing.
     * 
     * @param persistentClass
     *            the class type you'd like to persist
     */
    public GenericHibernateDAO(final Class<T> persistentClass) {
	this.persistentClass = persistentClass;
    }

    /**
     * {@inheritDoc}
     */
    public List<T> getAll() {
	return hibernateTemplate.loadAll(this.persistentClass);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public List<T> getAllDistinct() {
	Collection result = new LinkedHashSet(getAll());
	return new ArrayList(result);
    }

    /**
     * {@inheritDoc}
     */
    public T get(PK id) {
	T entity = (T) hibernateTemplate.get(this.persistentClass, id);

	if (entity == null) {
	    log.warn("Uh oh, '" + this.persistentClass + "' object with id '"
		    + id + "' not found...");
	    throw new ObjectRetrievalFailureException(this.persistentClass, id);
	}

	return entity;
    }

    /**
     * {@inheritDoc}
     */
    public boolean exists(PK id) {
	T entity = (T) hibernateTemplate.get(this.persistentClass, id);
	return entity != null;
    }

    /**
     * {@inheritDoc}
     */
    public T save(T object) {
	return (T) hibernateTemplate.merge(object);
    }

    /**
     * {@inheritDoc}
     */
    public void remove(PK id) {
	hibernateTemplate.delete(this.get(id));
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public List<T> findByNamedQuery(String queryName,
	    Map<String, Object> queryParams) {
	String[] params = new String[queryParams.size()];
	Object[] values = new Object[queryParams.size()];

	int index = 0;
	for (String s : queryParams.keySet()) {
	    params[index] = s;
	    values[index++] = queryParams.get(s);
	}

	return hibernateTemplate.findByNamedQueryAndNamedParam(queryName,
		params, values);
    }

    public Class<T> getPersistentClass() {
	return persistentClass;
    }

}
